世界七大匪夷所思的自然現象（組圖）

Kawah Ijen Lake, Indonesia
印尼卡瓦伊真火山

Travellers flock to the Indonesian island of Java to see the magnificent Kawah Ijen volcano – but what they don’t expect to find is the stunning turquoise-hued caldera lake at the volcano’s summit. To add to the drama, bright, citrine-coloured stones and billows of white gasses surround the 1km-wide aquamarine lake in a spectacular show.
游客蜂擁著去印尼爪哇島是為了親眼目睹壯觀的卡瓦伊真火山——但他們從未想過能夠在火山頂上看到這藍綠交加的火山口湖。更令人嘆為觀止的是，檸檬黃色的明亮石頭和翻騰不息的白霧環繞籠罩著這一千米寬的海藍寶石般的火山口湖。

One element is responsible for the entire, striking scene: sulphur. The magma chamber below the volcano pours sulphuric gases into the lake. Combined with a high concentration of dissolved metals, the gases turn the water a brilliant shade of blue. They also render the Ijen crater-lake the world’s largest highly acidic lake with a pH of 0.5.
這震撼人心的景觀都要歸功于一種化學物質：硫磺。火山下的巖漿房向湖中排放硫磺氣體。大量被腐蝕了的金屬與硫磺氣體反應，使得湖水變成深藍色。事實上，pH值達0.5的伊真火山口湖是世界上酸性最高的湖泊。

“Hydrogen chloride released from Ijen volcano mixed with the lake and turned it into an acidic monstrosity that it is today,” writes Quora user Vinay Sisodia. “What makes this place even more stunning, especially at night, is shots of sulphuric gases that combust into glints of bright blue upon contact with air.”
Quora用戶維奈?西索迪亞這樣解釋道，“伊真火山還會釋放氯化氫，氯化氫混入湖水，造就了今天奇特的酸性湖泊。而這個地方更具震撼力的是，尤其在夜間，幾束硫磺氣體在與空氣接觸的過程中會迸發出閃爍的藍色光芒?！?/p>

Intrepid travellers can join three-hour hikes to the bank of the crater to experience the lake in person.
喜歡冒險的游客可以參加三小時游火山口湖岸的遠足活動，更好地親身體驗火山湖的壯觀。